Electromagnetic register apparatus

ABSTRACT

An electromagnetically operated register is disclosed of the type having a U-shaped pole piece with one leg extending through the coil. The armature is linked to a separate ratchet arm, which is formed of plastic or other lightweight material and biased to the locking position by a leaf spring. The core slidably engages in the frame and serves as the support for the coil and as a keeper for the ratchet-operating mechanism, with a single pin retaining these components in assembled relation with the frame. The number wheels and index pinions comprise a subassembly, including the two pinion axles, having journal and snap engagement with the main frame.

United States Patent 1 I [111 3,725,648 Schmick et al. 1 Apr. 3, 1973 [541 ELECTROMAGNETIC REGISTER 2,822,983 2/1958 Sengebusch ..235 92 c APPARATUS lS(chlenburg amm Inventors: 'llhlssell l l g fi g al y 3,204,869 9/1965 Zumkeller ..235/92 0 acyno, iwau ee, 0t 0 IS. [73] Assignee: Badger Meter, Inc., Milwaukee Primary Emmi"er R' Skudy Wis Attorney-Albert H. Pendleton et al.

[22] Filed: June 24, 1971 [57] ABSTRACT [211 App]. No.: 156,352 An electromagnetically operated register is disclosed of the type having a U-shaped pole piece with one leg extending through the coil. The armature is linked to a 2% 235/92 tak gfig separate ratchet arm, which is formed of plastic or i 21 24 other lightweight material and biased to the locking 1 0 can: 6 position by a leaf spring. The core slidably engages in 1 l l the frame and serves as the support for the coil and as a keeper for the ratchet-operating mechanism, with a [56] References cued single pin retaining these components in assembled UNITED STATES PATENTS relation with the frame. The number wheels and index pinions comprise a subassembly, including the two 2,497,466 2/1950 Olson ..3l0/34 inion axles, having journal and snap engagement with 3,580,498 5/1971 La Pointe ....235/92 C th ai f am 3,268,7[4 8/1966 Wales ....235/92 C 2,998,187 8/1961 Wollar ..235/92 C 20 Claims, 7 Drawing Figures qoe 89 ELECTROMAGNETIC REGISTER APPARATUS This invention relates to improvements in electromagnetic registering devices having a plurality of sequentially operated indicator wheels motivated by a ratchet arrangement. More particularly it relates to such devices with an improved interlocking assembly of register components and an improved ratchet operating mechanism.

BACKGROUND OF THE INVENTION In several types of registering devices currently used, an electrom agnet is used to motivate a ratchet-operating armature in response to electrical impulses. These pulses may be derived from a source indicative of a quantity being sensed remotely from the register. A sensing device transmits electrical impulses to an electromagnet of a solenoid in the register which, when such impulses are received, activates an indexing armature of the registering device. The armature is coordinated with a ratchet wheel associated with a set of indicator wheels. When the armature is moved, the ratchet is rotated and the indicator wheels of the registering device are motivated to register the quantity being measured. One specific example of a use of such a register is in measuring the flow of liquid through a conduit as referred to in Dunn et al. U. S. Pat. No. 3,118,075 and Fyfe U. S. Pat. No. 3,561,835.

One prior registering device is assembled on a plastic frame with the coil ofthe solenoid wound on the frame and not removable therefrom. One leg of a U-shaped core extends through the frame, within the coil. The

ratchet-operating mechanism includes a metal armature spanning the distal end portions of the core and having ratchet-indexing fingers at one end of the armature. The other leg of the core retains the pivot end of the armature in position in the frame. A coil spring under tension between the frame and the armature holds the armature away from one leg of the core of the magnet, and thus the spring holds the indexing fingers of the armature in the locking position. When the magnet is energized, the armature is drawn to the core against the tension of the spring. This movement engages the ratchet-operating fingers on the end of the armature with the ratchet wheel, causing it to rotate and move a set of indicator wheels.

One of the shortcomings of this prior device is that the coil of the electromagnet is formed on the frame of the registering device, thus making the core an integral structure with the frame and necessitating a careful winding operation for forming the coil. The winding of the coil on the frame creates a complicated assembling operation for the entire device.

A second shortcoming is that the entire ratchet finger and armature member for indexing the ratchet wheel is made of a ferromagnetic metal. The spring holding the indexing finger out of engagement with the ratchet wheel must be strong enough to overcome the weight of this member but be light enough to permit ready movement when the magnet is energized. Due to the mass of this member relative to the strength of the spring the armature may easily index the ratchet wheel due to accidental jolting or shaking of the device. Such accidental actuations often occur during shipment unless special packing precautions are taken.

It is an object of this invention to provide an improved register apparatus overcoming the aforenoted problems.

It is another object of this invention to provide an improved register which is simple and economical to assemble.

It is another object of the present invention to provide a register apparatus which is conveniently disassembled in subparts and which is readily assembled from numerous subassemblies.

A further object of the invention is to provide a register device in which a ratchet-operating mechanism includes a lightweight armature not readily jarred by mishandling and shock during shipment.

A further object of the invention is to provide a registering device having a removable coil which may be wound separately from the frame member of the register.

SUMMARY OF THE INVENTION In carrying out this invention in one illustrative form a register device is provided including a frame member on which a subunit assembly of indicator wheels may be releasabl y engaged and a ferromagnetic core which may also be releasably engaged on the frame. The core of the magnet is mounted in slots in the frame of the register. The core supports the coil, which is wound on a bobbin shaped to fit the core, and serves-as a keeper for separate armature and ratchet components. A fastening pin engages a portion of the core outside the coil to retain the coil, core, ratchet-operating mechanism and the frame member in assembled relation. Thus, when the pin is inserted in the frame and engage in the core, the register is easily and simply fastened together to form a complete-operational device.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings, one preferred embodiment is illustrated by way of an example of the invention. In these drawings:

FIG. 1 is a perspective view of the cover and indicator wheels of a register assembly employing teachings of the present invention;

FIG. 2 is a perspective view of the assembled, internal components of the register shown in FIG. 1;

FIG. 3 is a sectional view of the register shown in FIG. 2, taken along the line 33 of FIG. 5;

FIG. 4 is an end view of the register shown in FIG. 2;

FIG. 5 is a plan view of the register shown in FIG. 2;

FIG. 6 is a view in cross section of the register, shown in FIG. 2, taken along the line 6-6 of FIG. 5; and

FIG. 7 is an exploded view in perspective of some of the elements of the ratchet-operating mechanism shown in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIGS. 13, a register 1 is supported on a base member 2. A removable cover 4 extends over the register mechanism and engages the base. The internal register components include a unitary frame member 6 and an indicator assembly 8 mounted in this frame and motivated by a ratchet wheel 10. A'ratchetoperating mechanism 12 is disposed on the-frame 6 to engage the ratchet wheel. When motivated by electrical impulses through leads 13, the ratchet-operating mechanism rotates the ratchet wheel which in turn rotates the indicator mechanism to provide a visible registration of the subject matter being metered.

The indicator mechanism 8 comprises a plurality of indicator wheels 14 shown in the drawing, particularly FIG. 5, as having Arabic numbers 16. These indicator wheels or number wheels are journaled on a spindle 18 supported at one end in terminal plate 20 and at the other end in frame wall 19. All of the indicator wheels are held in proper position relative to each other on the when not engaged by the indexing finger 52. When the lug portion 46 of the ratchet arm is inserted in the socket 48 of the pole plate, these two components form a linkage in which the ratchet arm flexes readily in relation to the pole plate. The leaf spring 38 includes a centrally grooved hat-shaped base 56, which embraces the ratchet arm, and an extended flexible tongue 57 in compressive contact with the underside of the ratchet arm (FIG. 6).

In the assembly of the ratchet-operating mechanism with the frame member 6, the ratchet arm 36 is I received between a pair of spaced brackets 58 of frame spindle 18 by a flat spring'22 mounted atone end on a parallel spindle 26. This spring is compressed between the terminal plate 20 and the first indicator wheel 14, with the mounting end clamped between plate 20 and a 6, with the studs 50 positioned in the saddle recesses 59 formed in these brackets. The stop finger 54 of the arm 36 is engaged with the teeth of ratchet wheel 10 by the force of spring 38. The base56 of the leaf spring exshoulder 27 on the spindle 26. Each of the indicator wheels 14 is provided with a series of peripheral lugs 24 and notches (not shown) so that they may be indexed successively in relation to each other. Spindle 26, also supported at one end in terminal plate and in frame member 6 at the other end, carries a series of integrating pinion gears 28 to successively advance indicator wheels 14 in the usual manner. At one end of spindle 18 a ratchet wheel 10 is provided on spindle 18 to initiate indexing of the indicator assembly. The ratchet wheel may be integrally formed with, attached or otherwise connected to the first indicator wheel 14.

It will be apparent from FIG. 6 that the terminal plate 20 is provided with a bifurcated stud 32 for engagement in a socket 34 in bottom panel35 of the frame member 6 to clasp the indicator assembly to the frame member, spindles 26 and 18 being supported in sockets 20a and 20b in the terminal plate as by a press fit therein. The ends of spindles l8 and 26 opposite the terminal plate 20 are engaged in openings 6a and 6b in the frame member. The indicator assembly may be subassembled separately from the register device by placing spring 22 on spindle 26, inserting one end of each spindle in the terminal plate 20 and then placing the indicator wheels 14 and the gears 28' on their respective spindles. When thus assembled, the indicator assembly may be attached to the frame member by inserting the distal ends of the spindles in the sockets 6a and 6b of the frame member and the stud 32 of the end plate in socket 34 of the frame member. The prongs of stud 32 are provided with shoulders 32 a which snap outward beneath panel 35 and with yieldable fingers 32b which press on the upper surface of this panel to maintain accurate, tight assembled relationship of the parts.

The ratchet-operating mechanism 12 is made up of a ratchet arm 36, a leaf spring 38, a pole plate 40, and a coil 41 having a winding 42 connected to leads l3, and a horseshoe-shaped or U-shaped core 44. Referring particularly to FIGS. 6 and 7, the rearward end of the ratchet arm includes a lug 46 provided to pivotally engage a socket 48 in an upwardly extending arm 49 of the L-shaped pole plate 40. Just forward of the lug 46, a pair of studs 50 extend laterally outwardly from the arm 36, and at the forward end an indexing finger portion 52 is extended for engagement with the teeth of the ratchet wheel 10. A second finger 54 is also provided on the ratchet arm for engagement with the teeth of ratchet wheel 10 to assist in the indexing advancement of wheel 10 and to lock the wheel against rotation tends between depending legs 60 of the brackets 58 to support the ratchet arm in the register. The socket 48 of the pole plate is slipped over the lug 46 of the arm 36 and an aperture 62 in one end of the pole plate 40 engages over a stud 64 extending from the base panel 35 of frame member 6. The engagement of the inner end of pole plate 40 on panel 35 provides the fulcrum for the operation of this plate. The brackets 58 and base 56 provide a fulcrum for the ratchet arm, and the pressure exerted by the leaf spring on the index finger end of the arm 36 pivots the lug 46 and the socket end of the pole plate 40 to their lowermost positions, i.e., with the pole plate retracted from core 44.

The coil 42 is wound upon a bobbin 66 having a centrally disposed passage through which one leg of the horseshoe-shaped core 44 fits, see FIGS. 3 and 6.

The frame 6 is a unitary body, as of molded plastic. In addition to the, side wall 19, base panel 35 and brackets 58 referred to above, the frame includes a side wall 68 opposite and generally parallel to wall 19, and a top plate 70. Plate 70 joins the side walls 19 and 68 along one edge, at one end, and panel 35 joins these walls along an opposite edge, at the opposite end. As seen in FIG. 4, wall 68 is of a configuration to be complemented by plate 20, which plate includes an alignment tab 72 (FIGS. 2 and 5) engaging this wall. A bracket section 74 (FIG. 4) joins plate 35 and wall 68 along the edge of plate 20.

With continuing reference to FIG. 4, plate 35 includes a shelf portion 76 having an upper surface lying in a plane in spaced opposed relation to the lower edges of walls 19 and 68, thus defining slots 78 (FIG. 4) and 80 (FIG. 2) therebetween. L-shaped lugs 82 at the lower outer ends of the walls 19 and 68 define slots 84 and 86 opposed to slots 78 and 80, respectively. These slots 78, 80,. 84 and 86 form a guideway or channel through the frame member 6, as best seen in FIG. 4, and permit the core to be inserted in slidable and releasable engagement into the frame member.

In assembly, the core 44 is inserted into the frame through slots 78 and 84, and then the coil 41 is introduced over one leg 88 of the core. Meanwhile, the pole plate 40, ratchet arm 36 and spring 38 have been placed in position as referred to above. The core is then advanced through the bobbin and through slots 80 and 86, with core leg 88 passing between the spring 38 and pole plate 40 and the other leg 89 passing over plate 40 above stud 64. Thus the core legs serve as keepers to retain the ratchet mechanism in assembled position. I

Thereby thecore is seated on the 'frame member and secures the components or the solenoid and the associated' components of the ratchet-operating mechanism in the frame member.

As seen most clearly in FIG. 6, leg 88 of the core is positioned in close proximity to the pole plate or armature 40. A protrusion 90 on plate 40 assures nonsticking contact between these components during operation of the device.

When the indicator assembly 8 and ratchet-operating mechanism 12 have been assembled with the solenoid (core-and coil) components in the frame member 6, a fastener pin such as screw 92 is inserted through the base 2 and secured to the extended leg 89 of the core 44. The base is thereby affixed to the frame, and the components of the register are secured to each other in assembled relationship on the base.

In use, the register receives electrical pulses from a remote sensing device (not shown) through leads 13 which have been affixed to terminals 94 (FIG. 3). Upon application of each predetermined pulse to the coil 41, core 44 becomes a temporary magnet, attracting pole plate 40. Lug 46 at the rearward end of the arm 36 is moved upwardly rotating the arm 36 in the saddle 59, and the indexing finger 52 is depressed onto the next tooth of ratchet wheel 10. In the same movement, stop 54 is moved out of engagement with the teeth of the ratchet wheel, thereby permitting the ratchet wheel to be advanced by finger 52. Also in the same movement, the leaf spring 38 is forced downwardly by the armature against the bias of the spring.

Correspondingly, each time the coil 41 is deenergized, pole plate 40 is released from the core. Spring 38 then is permitted to flex to disengage the indexing finger 52 from the ratchet wheel and to engage finger 54. It will be apparent from the foregoing description that the ratchet wheel is indexed each time the core is magnetized and released, according to the distance between each of the teeth and the predetermined relationship between the arrangement of teeth and the indexing fingers on the arm 36. The remote sensing device is accordingly designed to energize the coil only on such occasions as are significant in measuring the material being metered.

It has been found particularly desirable to form the arm 36 from a lightweight wear resistant plastic such as Celcon. This permits the use of a lightweight leaf spring which is readily overcome when the core of the magnet is energized, while at the same time assuring that the indexing fingers of the armature will be held from engaging and advancing the ratchet wheel. This is advantageous in the handling and shipment of the register because it avoids accidentally indexing the indicator wheels as a result of jars or jolts. The structure of the ratchet-operating mechanism thus permits handling and shipment of the register with a minimum of care and packing. Subsequent delays in installation are likewise avoided as the register is received in a properly indexed starting position.

The configuration of the mechanical linkage of the pole plate and the ratchet arm further provides a counterbalancing arrangement which assists in avoiding unintentional indexing from jarring or jolting of the register, both in shipment and when installed in use.

It will also be appreciated that the illustrated register is very simple in construction and extremely simple and economical to assemble.

It will be seen that an improved register device has been provided which meets the objects outlined above.

While a particular embodiment of this invention is shown above, it will be understood, of course, that the invention is not limited'thereto, since many modifications may be made by those skilled in the art, particularly in light of the teachings herein. It is contemplated, therefore, by the appended claims, to cover any such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. An electromagnetic register mechanism c0mprising a frame, register means having a ratchet wheel, a ratchet arm pivotally mounted on said frame for engaging said ratchet wheel, a spring member disposed to retain said ratchet arm in such pivotal mounting and to bias said arm to one predetermined position, a core member and an actuating coil each independent of said frame, said core member having slidable interlocking engagement with said frame and supporting said spring in position to so retain said ratchet arm, and said actuating coil being slidably engaged on said core member, whereby said ratchet arm, spring member, core member and coil are supported on said frame by such slidable interlocking engagement of said core member with said frame.

2.An electromagnetic register mechanism as in claim 1 including an armature plate pivotally mounted on said frame adjacent said core member, said arm being pivotally connected to said plate to be driven thereby against the force of said spring member when said plate is attracted toward said core member.

3. An electromagnetic register mechanism as in claim 2 wherein said arm is vof nonferromagnetic material.

4. An electromagnetic register mechanism as in claim 2 wherein said core member is U-shaped, one end of said plate having telescopic engagement with a portion of said frame, one leg of said core member retaining said plate in such telescopic engagement with said portion of said frame and the other leg of said core member retaining said spring member.

5. An electromagnetic register mechanism as in claim 4 wherein said frame is a unitary member formed with slots for slidably receiving and supporting said core member.

6. An electromagnetic register mechanism as in claim 5 wherein said register means includes a register assembly comprising said ratchet wheel to be engaged by said ratchet arm, a mounting element having an interlocking connection with said frame, and counter mechanism including a spindle having one end supported in said mounting element and its opposite end supported in said frame.

7. An electromagnetic register mechanism as in claim 1 wherein said spring member engages said ratchet arm adjacent the pivotal mounting of said arm on said frame and at a point remote from such pivotal mounting.

8. An electromagnetic register comprising a frame member, an indicator assembly supported on said frame member and including a ratchet wheel, and a ratchet-operating mechanism releasably interlocked onto said frame member and engageable upon said ratchet wheel, said ratchet operating mechanism including a core member and a coil member each independent of said frame member, said core member fastener means for retaining said coil member in such interlocking engagement with said frame.

10. An electromagnetic register as in claim 8 including a base member, and a fastener pin securing said frame member to said basemember and securing said core member in such interlocking engagement with said frame member.

11. An electromagnetic register as in claim 8 wherein said frame member is provided with at least one socket, and said indicator assembly includes asupport member having a stud engaged in said socket'for interlocking said indicator assembly onto said frame member. I

12. An electromagnetic register as in claim 11 wherein said indicator assembly includes atleast one spindle, one end of said spindle being engaged in said support member and the other end of said spindle being engaged in said frame member.

13. An electromagnetic register as in claim 8 wherein said frame includes spaced plates for receiving said coil member therebetween and said plates define channels for slidably receiving said core in such interlocking engagement.

14. An electromagnetic ratchet-operating mechanism comprising a frame, an electromagnet supported on said frame and including a core-member, a ratchet arm positioned on one side of said core, said ratchet arm being pivotable about a fulcrum on said frame and having ratchet operating elements disposed to operably engage a ratchet wheel in two positions of movement of such arm about such fulcrum, a movable pole plate positioned adjacent an opposite side of said 'core and having a flexible connection to said arm, said electromagnet being operable to attract said pole plate toward said core and thereby to rotate said arm through said flexible connection about such fulcrum to move said arm to one of said positions, and a spring urging said arm to the other of said positions when said magnet is de-energized.

l5. An electromagnetic ratchet-operating mechanism comprising a frame, a lightweight nonferromagnetic ratchet arm pivotable about a fulcrum on said frame andincluding a pair of ratchet operating fingers disposed to operably engage a ratchet wheel in two positions of movement of said arm about such fulcrum, a movable pole plate having a flexible connection to said arm, an electromagnet including a core having atleast one pole adjacent said pole plate, said electromagnet being operable to attract said pole plate toward said core and thereby to rotate said arm through said flexi 'ble connection about such fulcrum to move said arm to one of said positions, and a leaf spring urging said arm to the other of said positions when said magnet is deenergized. 7

16. An electromagnetic ratchet-operating mechanism com rising a frame a lightweight nonferromagnetic ratc et arm plvotable about a ulcrum on said frame and including a pair of ratchet operating fingers disposed to operably engage a ratchet wheel in two positions of movement of said arm'about such fulcrum,

a movable pole plate having a flexible connection to said arm, an electromagnet including a core having at least one pole adjacent said pole plate, said electromagnet being operable to attract said pole plate toward said core and thereby to rotate said arm through said flexible connection about such fulcrum to move said arm to one of said positions, and a spring disposed intermediate said arm and said pole plate and urging said arm to the other of said positions when said magnet is de-energized.

17. An electromagnetic ratchet-operating mechanism comprising a frame, a lightweight nonferromagnetic ratchet arm pivotable about a fulcrum on said frame and including a pair of ratchet operating fingers disposed to operably engage a ratchet wheel in two positions of movement of said arm about such fulcrum, amovable pole plate having a flexible connection to said arm, an electromagnet including a core having at least one pole adjacent said pole plate and a coil member slidably and releasably engaged on said core, said electromagnet being operableto attract said pole plate toward said core and thereby to rotate said arm through said flexible connection about such fulcrum to move said arm to one of said positions, and a spring urging said arm to the other of said positions when said magnet is de-energized. 1

18. The ratchet-operating mechanism of claim 17 wherein the fulcrum of said arm is disposed intermediate the flexible connection of said arm to said pole plate and the ratchet wheel engagement portion of said arm.

19. The ratchet-operating mechanism of claim 17 wherein said spring engages said arm intermediate said fulcrum and the ratchet wheel engagement portion of said arm.

20.v An electromagnetic register comprising indicator means having a ratchet wheel, and a ratchet-operating mechanism as' in claim 17, wherein said ratchet arm is disposed adjacent said ratchet wheel and positioned to 

1. An electromagnetic register mechanism comprising a frame, register means having a ratchet wheel, a ratchet arm pivotally mounted on said frame for engaging said ratchet wheel, a spring member disposed to retain said ratchet arm in such pivotal mounting and to bias said arm to one predetermined position, a core member and an actuating coil each independent of said frame, said core member having slidable interlocking engagement with said frame and supporting said spring in position to so retain said ratchet arm, and said actuating coil being slidably engaged on said core member, whereby said ratchet arm, spring member, core member and coil are supported on said frame by such slidable interlocking engagement of said core member with said frame.
 2. An electromagnetic register mechanism as in claim 1 including an armature plate pivotally mounted on said frame adjacent said core member, said arm being pivotally connected to said plate to be driven thereby against the force of said spring member when said plate is attracted toward said core member.
 3. An electromagnetic register mechanism as in claim 2 wherein said arm is of nonferromagnetic material.
 4. An electromagnetic register mechanism as in claim 2 wherein said core member is U-shaped, one end of said plate having telescopic engagement with a portion of said frame, one leg of said core member retaining said plate in such telescopic engagement with said portion of said frame and the other leg of said core member retaining said sprinG member.
 5. An electromagnetic register mechanism as in claim 4 wherein said frame is a unitary member formed with slots for slidably receiving and supporting said core member.
 6. An electromagnetic register mechanism as in claim 5 wherein said register means includes a register assembly comprising said ratchet wheel to be engaged by said ratchet arm, a mounting element having an interlocking connection with said frame, and counter mechanism including a spindle having one end supported in said mounting element and its opposite end supported in said frame.
 7. An electromagnetic register mechanism as in claim 1 wherein said spring member engages said ratchet arm adjacent the pivotal mounting of said arm on said frame and at a point remote from such pivotal mounting.
 8. An electromagnetic register comprising a frame member, an indicator assembly supported on said frame member and including a ratchet wheel, and a ratchet-operating mechanism releasably interlocked onto said frame member and engageable upon said ratchet wheel, said ratchet operating mechanism including a core member and a coil member each independent of said frame member, said core member slidably engaging said coil member and having slidable interlocking engagement with said frame member for supporting said core and coil members on said frame member by such slidable and interlocking engagement.
 9. An electromagnetic register as in claim 8 including fastener means for retaining said coil member in such interlocking engagement with said frame.
 10. An electromagnetic register as in claim 8 including a base member, and a fastener pin securing said frame member to said base member and securing said core member in such interlocking engagement with said frame member.
 11. An electromagnetic register as in claim 8 wherein said frame member is provided with at least one socket, and said indicator assembly includes a support member having a stud engaged in said socket for interlocking said indicator assembly onto said frame member.
 12. An electromagnetic register as in claim 11 wherein said indicator assembly includes at least one spindle, one end of said spindle being engaged in said support member and the other end of said spindle being engaged in said frame member.
 13. An electromagnetic register as in claim 8 wherein said frame includes spaced plates for receiving said coil member therebetween and said plates define channels for slidably receiving said core in such interlocking engagement.
 14. An electromagnetic ratchet-operating mechanism comprising a frame, an electromagnet supported on said frame and including a core member, a ratchet arm positioned on one side of said core, said ratchet arm being pivotable about a fulcrum on said frame and having ratchet operating elements disposed to operably engage a ratchet wheel in two positions of movement of such arm about such fulcrum, a movable pole plate positioned adjacent an opposite side of said core and having a flexible connection to said arm, said electromagnet being operable to attract said pole plate toward said core and thereby to rotate said arm through said flexible connection about such fulcrum to move said arm to one of said positions, and a spring urging said arm to the other of said positions when said magnet is de-energized.
 15. An electromagnetic ratchet-operating mechanism comprising a frame, a lightweight nonferromagnetic ratchet arm pivotable about a fulcrum on said frame and including a pair of ratchet operating fingers disposed to operably engage a ratchet wheel in two positions of movement of said arm about such fulcrum, a movable pole plate having a flexible connection to said arm, an electromagnet including a core having at least one pole adjacent said pole plate, said electromagnet being operable to attract said pole plate toward said core and thereby to rotate said arm through said flexible connection about such fulcrum to move said arm to one of said positions, and a leaf spring urging said arm to the other of saId positions when said magnet is de-energized.
 16. An electromagnetic ratchet-operating mechanism comprising a frame, a lightweight nonferromagnetic ratchet arm pivotable about a fulcrum on said frame and including a pair of ratchet operating fingers disposed to operably engage a ratchet wheel in two positions of movement of said arm about such fulcrum, a movable pole plate having a flexible connection to said arm, an electromagnet including a core having at least one pole adjacent said pole plate, said electromagnet being operable to attract said pole plate toward said core and thereby to rotate said arm through said flexible connection about such fulcrum to move said arm to one of said positions, and a spring disposed intermediate said arm and said pole plate and urging said arm to the other of said positions when said magnet is de-energized.
 17. An electromagnetic ratchet-operating mechanism comprising a frame, a lightweight nonferromagnetic ratchet arm pivotable about a fulcrum on said frame and including a pair of ratchet operating fingers disposed to operably engage a ratchet wheel in two positions of movement of said arm about such fulcrum, a movable pole plate having a flexible connection to said arm, an electromagnet including a core having at least one pole adjacent said pole plate and a coil member slidably and releasably engaged on said core, said electromagnet being operable to attract said pole plate toward said core and thereby to rotate said arm through said flexible connection about such fulcrum to move said arm to one of said positions, and a spring urging said arm to the other of said positions when said magnet is de-energized.
 18. The ratchet-operating mechanism of claim 17 wherein the fulcrum of said arm is disposed intermediate the flexible connection of said arm to said pole plate and the ratchet wheel engagement portion of said arm.
 19. The ratchet-operating mechanism of claim 17 wherein said spring engages said arm intermediate said fulcrum and the ratchet wheel engagement portion of said arm.
 20. An electromagnetic register comprising indicator means having a ratchet wheel, and a ratchet-operating mechanism as in claim 17, wherein said ratchet arm is disposed adjacent said ratchet wheel and positioned to engage and operate said ratchet wheel. 